Simple SOHO setup help

I am a new user to Shorewall and would like to ask for some help on initial
configuration. My setup is a very simple home network with a single NAT
router/nameserver/gateway and a single computer on the LAN side.

This computer needs to be able to surf the web (ports 80, 443),
send/receive email (port 465), SSH local and remote (port 22), respond to
pings.

I also have a camera sending RTSP stream on port 554.

Currently, these ports are open in the router.

The first question relates to defining zones. I think I need only one zone
being the local LAN.

I looked at the universal config but this seems to be for a computer
directly on the web, not via a router.

-Chris Wilkinson